No problem. Once I hit 20, I bought my class specific item for whatever faction I liked based on their base stats. I leveled the faction to reputation level 2 so I could use Crucible marks to purchase gear. Attaining level is rather quick, as reputation earned through Vanguard and Crucible apply to your desired faction. I next leveled Vanguard and Crucible to reputation level 3 so I could make the most use of each individually. This allowed me to purchase gear, along with weapons / speeders from Crucible / Vanguard. The main key here should be getting Vanguard to 3, as you can only spend Vanguard marks on Vanguard items. As a quick note, once you hit reputation level 3 and beyond for any faction, you'll receive a legendary package in the postmaster. After attaining rank 3 in Vanguard / Crucible, I put my class specific faction aesthetic item back on my character and have not removed it since from any of my 3 characters. This has allowed me to continue receiving free legendary items from the faction of my choosing (I chose a different faction for each of my 3 characters), including weapons the faction rep does not even sell. I hope all of that was communicated clearly and that it helps.